HK1245311B - Foamable multi-component composition forming an insulating layer and its use - Google Patents

Description

The present invention relates to a foaming, insulating layer-forming multi-component composition and its use.

Polyurethanes are often used as adhesives for mounting, insulation, and fire protection foams. These can be applied, for example, as 1K (one-component), 2K (two-component) aerosol cans or as 2K cartridge foam. In the first case, the system requires high humidity to cure. In the latter two cases, curing is achieved via the polyol/water component. The hardener component, the isocyanate, has been considered a hazardous substance for a long time. Substances containing more than 1% free MDI must be labeled with "carcinogenic category 3; H351". Especially for on-site foams that are applied by the consumer, it would be very advantageous if the substances to which people come into contact were as harmless as possible.

A solution approach for this is so-called "low-MDI foams," in which isocyanate prepolymers with an isocyanate content of, for example, less than 1% or even 0.1% are used, as described, for example, in DE 102010038355 A1 or DE 10357093 A1.

Another solution approach is based on the use of "modified silanes" (also STP, silane-terminated polymer). These polymers, which often have a polyurethane or polyether backbone, harden via hydrolysis and polycondensation reaction of the alkoxy-silyl groups. Such foams are commercially available as insulating foams in pressurized cans. The can foams are generally foamed using a physical blowing agent. Such systems are, for example, known from WO 2000/004069 A1, US 2006/189705 A, WO 2013/107744 A1, or WO 2013/045422 A1.

A disadvantage for the fire performance of pressurized foams that use physical blowing agents which also serve as solvents for the prepolymers is that only low densities can be achieved. In order to generate stable ashes in case of fire, generally densities greater than 100 g/l are required, which are hardly achievable with conventional pressurized foams. Furthermore, the limited applicability of fillers necessary for good fire protection properties is another disadvantage, because settling behavior, valve operation and storage stability are problematic when combined with the prepolymers. Another disadvantage is the re-foaming after the foam has been dispensed from the can, since the foam continues to react with humidity in the air. After the pressurized foams have cured due to humidity in the air, the curing "in bulk" occurs only slowly or not at all, i.e., normal curing on the surface, but slowed curing in the depth, since there is a lack of moisture.

In addition to single-component STP aerosol foams, two- or multi-component systems are also known, such as those described in EP 1829908 A1, EP 2725044 A1, or WO 2014/064039 A1. However, the known STP aerosol foams and two-component systems are not fire-retardant foams and do not contain fire-retardant additives.

The invention is based on the task of providing foams, in particular local foams, which do not have the mentioned disadvantages of known systems and which are suitable for fire protection.

This task is solved by the composition according to claim 1. Preferred embodiments are to be found in the dependent claims.

The subject of the invention is therefore a foaming, insulating layer-forming multi-component composition comprising at least one alkoxysilane-functional polymer which is terminated and/or has alkoxy-functional silane groups of the general formula (I) along the polymer chain: -Si(R1)m(OR2)3-m     (I), wherein R1 represents a linear or branched C1-C16 alkyl group, R2 represents a linear or branched C1-C6 alkyl group, and m represents an integer from 0 to 2, together with at least one fire-retardant additive forming an insulating layer, with a blowing agent mixture and with a crosslinking agent, wherein the fire-retardant additive forming an insulating layer is used in an amount of 12 to 60 wt.-% based on the entire multi-component composition.

According to the invention, the individual components of the propellant mixture are separated from each other in a reaction-inhibited manner before use of the composition. Furthermore, the crosslinking agent is separated in a reaction-inhibited manner from the alkoxysilane-functional polymer before use of the composition, in order to prevent curing of the polymer prior to use of the composition.

In the sense of the invention, a polymer is a molecule with six or more repeating units, which can have a structure that is linear, branched, star-shaped, coiled, hyperbranched, or cross-linked. Polymers can have a single type of repeating unit ("homopolymers") or they can have more than one type of repeating unit ("copolymers"). As used herein, the term "polymer" includes prepolymers, which may also include oligomers having 2 to 5 repeating units, such as the alkoxysilane-functional compounds used as component A, which react with each other in the presence of water to form Si-O-Si bonds, as well as the polymeric compounds formed by the above-mentioned reaction.

For better understanding of the invention, the following explanations of the terminology used herein are considered useful. In the sense of the invention: "chemical intumescence" means the formation of a bulky, insulating ash layer by coordinated compounds that react with each other when exposed to heat; "physical intumescence" means the formation of a bulky, insulating layer by expansion of a compound which, without a chemical reaction between two compounds, releases gases when exposed to heat, thereby increasing the volume of the compound several times over its original volume; "heat-insulating layer-forming" means that in case of fire, a solid microporous carbon foam is formed, such that the fine-pored and thick foam layer formed, the so-called ash crust, provides insulation against heat depending on its composition; a "carbon source" is an organic compound,which leaves behind a carbon framework due to incomplete combustion and does not fully burn into carbon dioxide and water (carbonization); these compounds are also called "carbon framework formers"; is an "acid former" a compound that forms a non-volatile acid under the influence of heat, i.e., above approximately 150°C, for example through decomposition, and thereby acts as a catalyst for carbonization; additionally, it can contribute to reducing the viscosity of the binder melt; the term "dehydrogenation catalyst" is used synonymously with this; is a "gas former" a compound that decomposes at elevated temperatures, releasing inert, i.e., non-flammable gases, and possibly causes the softened binder to expand into a foam (intumescence); is an "ash crust stabilizer" a so-called framework-forming compound,which stabilizes the carbon framework (ash crust), formed by the interaction of carbon formation from the carbon source and the gas from the gas generator, or by physical intumescence.

Advantageously, the alkoxysilane-functional polymer comprises a base structure selected from the group consisting of polyether, polyester, polyether ester, polyamide, polyurethane, polyesterurethane, polyetherurethane, polyetheresterurethane, polyamideurethane, polyurea, polyamine, polycarbonate, polyvinyl ester, polyacrylate, polyolefin, such as polyethylene or polypropylene, polyisobutylene, polysulfide, rubber, neoprene, phenolic resin, epoxy resin, and melamine. The base structure can be structured linearly or branched (linear base structure with side chains along the chain of the base structure) and contains terminating groups, i.e., as end groups of a linear base structure or as end groups of the linear base structure and as end groups of the side groups, alkoxy-functional silane groups, preferably at least two alkoxy-functional silane groups.

The alkoxy-functional silane group has the general formula (I): -Si(R1)m(OR2)3-m        (I), where R1 is a linear or branched C1-C16 alkyl group, preferably a methyl or ethyl group, R2 is a linear or branched C1-C6 alkyl group, preferably a methyl or ethyl group, and m is an integer from 0 to 2, preferably 0 or 1. Most preferred are silane groups with at least two alkoxy functions, i.e., di-functional (m = 1) or tri-functional (m = 0), and the alkoxy group is a methoxy or ethoxy group.

Preferred is the alkoxy-functional silane group over a group, such as another functional group (X = e.g., -S-, -OR, -NHR, -NR2), which can itself act as an electron donor or contains an atom that can act as an electron donor, bound to the basic framework, wherein the two functional groups, i.e., the other functional group and the alkoxy-functional silane group, are connected via a methylene bridge (-X-CH2-Si(R1)m(OR2)3-m). This causes an electronic interaction (back-bonding) between the silicon atom and the electron donor, where electron density is shifted from the donor to the silicon atom, resulting in a weakening of the Si-O bond, which in turn leads to a significantly increased reactivity of the Si-alkoxy groups. This phenomenon is known as the so-called α-effect. Such compounds are also referred to as α-silanes. In addition, however, so-called γ-silanes or other types of silanes can also be used.

The most preferred are polymers in which the base chain is terminated with silane groups via a urethane group or an ether group, such as, for example, polyether terminated with dimethoxy(methyl)silylmethylcarbamate, polyether terminated with diethoxy(methyl)silylmethylcarbamate, polyether terminated with trimethoxysilylmethylcarbamate, polyether terminated with triethoxysilylmethylcarbamate, or mixtures thereof.

Examples of suitable polymers include silane-terminated polyethers (e.g., Geniosil® STP-E 10 and Geniosil® STP-E 30 from Wacker Chemie AG; MS polymers from Kaneka Corporation (in particular MS-203, MS-303, SAX260, SAX350, SAX400, SAX 220, S154, S327, S227, SAX725, SAX510, SAX520, SAX530, SAX580, SAT010, SAX015, SAX770, SAX220, SAX115, (polyether backbone)), and silane-terminated polyurethanes (e.g., Polymer ST61, Polymer ST75, and Polymer ST77 from Evonik Hanse, Desmoseal® S XP 2458, Desmoseal® S XP 2636, Desmoseal® S XP 2749, Desmoseal® S XP 2821 from Bayer, SPUR+*1050MM, SPUR+*1015LM, SPUR+* 3100HM, SPUR+* 3200HM from Momentive).

As alternative polymers, those are preferably used where the alkoxy-functional silane groups are not (only) terminally incorporated into the polymer matrix, but are specifically distributed along the chain of the base polymer. Through the incorporated multiple crosslinking units, important properties such as crosslinking density can be controlled. As a suitable example, the product line TEGOPAC® of Evonik Goldschmidt GmbH can be mentioned, such as TEGOPAC BOND 150, TEGOPAC BOND 250 and TEGOPAC SEAL 100 as well as GENIOSIL® XB 502, GENIOSIL® WP1 and GENIOSIL® WP2 of Wacker Chemie AG. With regard to this, the following documents are cited by way of example: DE 102008000360 A1, DE 102009028640 A1, DE 102010038768 A1 and DE 102010038774 A1.

The alkoxysilane-functional polymer can also be a mixture of two or more of the previously described polymers, which may be identical or different.

Depending on the chain length of the base structure, the alkoxy functionality of the polymer, and the position of the alkoxy-functional silane groups, the degree of crosslinking of the binder can be adjusted, thus influencing both the strength of the resulting coating and its elastic properties.

Usually, the amount of binder is 10 to 70 wt.%, preferably 15 to 65 wt.%, more preferably 20 to 55 wt.%, each based on the total composition.

According to the invention, the composition contains a crosslinking agent, in particular water. This results in a more homogeneous and faster hardening of the binder compared to a system that hardens through the humidity in the surrounding air. Thus, the hardening of the composition is largely independent of the absolute air humidity, and the composition reliably and quickly hardens even under extremely dry conditions.

The water content in the composition is preferably between 5 and 40 wt.%, more preferably between 10 and 30 wt.%, based on the entire composition.

As propellants, all common chemical propellants suitable for activation through a chemical reaction between two components are appropriate, i.e., they form a gas as the actual propellant. Preferably, the composition contains a propellant mixture comprising compounds that react with each other upon mixing, forming carbon dioxide (CO2), hydrogen (H2), or oxygen (O2).

In one embodiment, the propellant mixture includes an acid and a compound that can react with acids to form carbon dioxide.

As compounds that can react with acids to form carbon dioxide, carbonate and bicarbonate-containing compounds, particularly metal or (especially quaternary) ammonium carbonates, such as carbonates of alkali or alkaline earth metals, for example CaCO3, NaHCO3, Na2CO3, K2CO3, (NH4)2CO3, and the like, with chalk (CaCO3) being preferred. Various types of chalks with different particle sizes and surface structures, such as coated or uncoated chalks, or mixtures of two or more of them, can be used. Coated chalk types are preferably used because they react more slowly with the acid and thus ensure controlled foaming and well-adjusted foaming and hardening times.

As an acid, any acidic compound can be used that is capable of reacting with carbonate- or bicarbonate-containing compounds, releasing carbon dioxide, such as phosphoric acid, hydrochloric acid, sulfuric acid, ascorbic acid, polyacrylic acid, benzoic acid, toluenesulfonic acid, tartaric acid, glycolic acid, lactic acid; organic monocarboxylic, dicarboxylic, or polycarboxylic acids, such as acetic acid, chloroacetic acid, trifluoroacetic acid, fumaric acid, maleic acid, citric acid, or the like, aluminum dihydrogen phosphate, sodium hydrogen sulfate, potassium hydrogen sulfate, aluminum chloride, urea phosphate, and other acid-releasing chemicals or mixtures of two or more of them. The acid generates the gas as the actual propellant.

As an acidic component, an aqueous solution of an inorganic and/or organic acid can be used. Furthermore, buffered solutions of citric, wine, acetic, phosphoric acid, and the like can be used.

According to the invention, the content of acid component in the composition can be up to 41 wt.%, based on the polymer, with a content in the range between 10 and 35 wt.% being preferred, between 15 and 30 wt.% being more preferred, and between 18 and 28 wt.% being even more preferred.

In an alternative embodiment, the propellant mixture includes compounds that release hydrogen upon reaction with each other. For this purpose, reactions of: (i) one or more non-precious metals (e.g., aluminum, iron or zinc) with bases (e.g., one or more alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide or lithium hydroxide) or with one or more acids, as defined above for carbonates (preferably inorganic acid); (ii) metal hydrides (e.g., sodium hydride or lithium aluminum hydride) with water; or (iii) a compound having silicon-bound hydrogen atoms (e.g., polymethylhydrogensiloxane, also known as polymethylhydrosiloxane, but also other polyalkyl- or polyarylhudrosiloxanes) with proton donors (e.g., water). Suitable examples include linear polyhydrogensiloxanes, tetramers, copolymers of dimethylsiloxane and methylhydrosiloxane, trimethylsilyl-terminated polyhydrogensiloxanes, hydride-terminated polydimethylsiloxanes, triethylsilyl-terminated polyethyldihydrosiloxanes, hydride-terminated copolymers of polyphenylmethylsiloxane and methylhydrosiloxane, and the like.

These bonds are preferably present in an amount of 0.1 to 15 wt.%, more preferably from 3 to 13 wt.%, and most preferably from 4 to 7 wt.%, based on the entire composition.

In a further alternative embodiment, the propellant mixture includes compounds that can release oxygen upon reaction with each other, such as through the reaction of peroxides (e.g., hydrogen peroxide or hydrogen peroxide-releasing compounds, including solid compounds such as hydrogen peroxide-urea complex and urea phosphate) with metal oxides and/or bases.

These bonds are preferably present in an amount of 0.1 to 5 wt.%, more preferably from 1.5 to 4 wt.%, and most preferably from 2 to 3 wt.%, based on the entire composition.

According to the invention, the composition contains a damping layer-forming additive, wherein the additive can be either a single compound or a mixture of several compounds.

It is expedient to use as insulating layer-forming additives those which act by forming an expanded, insulating layer made of difficult-to-ignite materials, which is created under the influence of heat, thus protecting the substrate from overheating and thereby preventing or at least delaying changes in the mechanical and static properties of load-bearing components caused by heat. The formation of a bulky, insulating layer, namely an ash layer, can be achieved through the chemical reaction of a mixture of appropriately matched compounds that react with each other when exposed to heat. Such systems are known to experts under the term "chemical intumescence" and can be used according to the invention. Alternatively, the bulky, insulating layer can be formed by physical intumescence. Both systems can be used individually or together as a combination according to the invention.

For the formation of a swelling layer through chemical intumescence, at least three components are generally required: a carbon source, a dehydration catalyst, and a gas former, which are often contained in a binder. Upon exposure to heat, the binder softens and the fire protection additives are released, allowing them to react with each other in the case of chemical intumescence or to expand in the case of physical intumescence. Through thermal decomposition, the dehydration catalyst forms an acid, which acts as a catalyst for the carbonization of the carbon source. At the same time, the gas former decomposes thermally, producing inert gases that cause the carbonized (charred) material to expand, and possibly also the softened binder, resulting in the formation of a bulky, insulating foam.

In one embodiment of the invention, in which the insulating layer is formed by chemical intumescence, the insulation-layer-forming additive comprises at least one carbon-based framework-former, provided that the binder cannot be used as such, at least one acid-former, at least one gas-former, and at least one inorganic framework-former. The components of the additive are particularly selected so that they can develop a synergistic effect, with some of the compounds being able to fulfill multiple functions.

As a carbon source, the compounds commonly used in intumescent flame retardants and known to experts may be considered, such as starch-like compounds, for example starch and modified starch, and/or polyhydric alcohols (polyols), such as saccharides and polysaccharides, and/or a thermoplastic or thermosetting polymeric binder, such as a phenolic resin, urea resin, polyurethane, polyvinyl chloride, poly(meth)acrylate, polyvinyl acetate, polyvinyl alcohol, a silicone resin and/or rubber. Suitable polyols are polyols from the group of sugars, pentaerythritol, dipentaerythritol, tri-pentaerythritol, polyvinyl acetate, polyvinyl alcohol, sorbitol, EO-PO polyols. Pentaerythritol, dipentaerythritol or polyvinyl acetate are preferred.

It should be mentioned that the polymer used as a binder can also function as a carbon source in case of fire, meaning that the addition of an additional carbon source is not always necessary.

As dehydrating catalysts or acid-forming agents, the compounds commonly used in intumescent fire protection formulations and known to experts can be considered, such as a salt or ester of an inorganic, non-volatile acid, selected from sulfuric acid, phosphoric acid, or boric acid. Basically, phosphorus-containing compounds are used, which form a very wide range, since they span several oxidation states of phosphorus, such as phosphines, phosphine oxides, phosphonium compounds, phosphates, elemental red phosphorus, phosphites, and phosphates. Examples of phosphoric acid compounds include: monoammonium phosphate, diammonium phosphate, ammonium phosphate, ammonium polyphosphate, melamine phosphate, melamine resin phosphates, potassium phosphate, polyol phosphates such as pentaerythritol phosphate, glycerol phosphate, sorbitol phosphate, mannitol phosphate, dulcitol phosphate, neopentyl glycol phosphate, ethylene glycol phosphate, dipentaerythritol phosphate, and similar compounds. Preferably, a polyphosphate or ammonium polyphosphate is used as the phosphoric acid compound. Among melamine resin phosphates, compounds such as reaction products of Lamelite C (melamine-formaldehyde resin) with phosphoric acid are meant. Examples of sulfate compounds include: ammonium sulfate, ammonium sulfamate, nitroaniline bisulfate, 4-nitroaniline-2-sulfonic acid, and 4,4-dinitrosulfanilamide and similar compounds. As a boric acid compound, melamine borate can be mentioned as an example.

As gas-forming agents, the compounds commonly used in flame retardants and known to experts are considered, such as cyanuric acid or isocyanic acid and their derivatives, melamine and its derivatives. These include cyanamide, dicyanamide, dicyandiamide, guanidine and its salts, biguanide, melamine cyanurate, cyanic acid salts, cyanic acid esters and amides, hexamethoxymethylmelamine, dimelamine pyrophosphate, melamine polyphosphate, and melamine phosphate. Hexamethoxymethylmelamine or melamine (cyanuric acid amide) is preferably used.

Furthermore, components are suitable which do not limit their action to a single function, such as melamine polyphosphate, which acts both as an acid former and as a gas former. Further examples are described in GB 2 007 689 A1, EP 139 401 A1 and US-3 969 291 A1.

In one embodiment of the invention, in which the insulating layer is formed by physical intumescence, the insulating layer-forming additive comprises at least one thermally expandable compound, such as a graphite intercalation compound, also known as expanded graphite. These can also be contained in the binder, in particular homogeneously.

For example, expandable graphite may include well-known intercalation compounds of SOx, NOx, halogens and/or strong acids in graphite. These are also referred to as graphitic salts. Preferred expandable graphites are those that release SO2, SO3, NO and/or NO2 upon expansion at temperatures, for example, between 120 and 350°C. Expandable graphite may, for example, be present in the form of flakes with a maximum diameter ranging from 0.1 to 5 mm. Preferably, this diameter is in the range of 0.5 to 3 mm. Expandable graphites suitable for the present invention are commercially available. In general, expandable graphite particles are uniformly distributed in the fire protection elements according to the invention. However, the concentration of expandable graphite particles may also vary locally, in patterns, over areas and/or in a sandwich-like manner. With regard to this, reference is made to EP 1489136 A1.

In a further embodiment of the invention, the insulating layer is formed both by chemical and physical intumescence, so that the foam-forming additive comprises both a carbon source, a dehydrating catalyst and a gas generator as well as thermally expandable compounds.

The fire-retardant additive that forms a char layer also helps increase the density of the foams, as this can improve their fire protection properties. The foams generally have densities of approximately 160-300 g/cm³, measured according to DIN EN ISO 845.

The intumescent additive can be present in an amount of 12 to 60 weight-% in the composition. To achieve the highest possible intumescence rate, the proportion of the intumescent additive in the overall formulation is set as high as possible, while ensuring that the viscosity of the composition does not become too high, so that the composition can still be processed easily. Preferably, the proportion is 15 to 30 weight-%, based on the entire composition.

Since the ash crust formed during a fire is usually unstable and can be easily blown away by air currents, depending on its density and structure, which negatively affects the insulating effect of the coating, at least one ash crust stabilizer is preferably added to the components listed above. The basic principle of action is that the very soft carbon layers that form are mechanically hardened by inorganic compounds. The addition of such an ash crust stabilizer contributes significantly to the stabilization of the intumescent crust during a fire, as these additives increase the mechanical strength of the expanding layer and/or prevent it from dripping.

As ash crust stabilizers or framework formers, the compounds commonly used in fire protection formulations and known to experts can be considered, for example expanded graphite and particulate metals such as aluminum, magnesium, iron, and zinc. The particulate metal may be present in the form of powder, flakes, scales, fibers, threads, and/or whiskers, with the particulate metal in the form of powder, flakes or scales having a particle size of ≤50 µm, preferably from 0.5 to 10 µm. In the case of using the particulate metal in the form of fibers, threads and/or whiskers, a thickness of 0.5 to 10 µm and a length of 10 to 50 µm is preferred. As an ash crust stabilizer, alternatively or additionally, an oxide or a compound of a metal from the group of aluminum,Can be used in a group containing magnesium, iron or zinc, particularly iron oxide, preferably ferric oxide, titanium dioxide, a borate such as zinc borate and/or a glass frit from low-melting glasses with a melting temperature of preferably at or above 400°C, phosphate or sulfate glasses, melamine polyzinc sulfates, ferro-glasses or calcium borosilicates. The addition of such an ash crust stabilizer contributes to a significant stabilization of the ash crust in the event of a fire, since these additives increase the mechanical strength of the expanding layer and/or prevent it from dripping. Examples of such additives are also found in US 4,442,157 A, US 3,562,197 A, GB 755,551 A and EP 138,546 A1.

In addition, ash crust stabilizers such as melamine phosphate or melamine borate may be present.

Optionally, the inventive composition may contain one or more flame retardants, such as phosphate esters, halogen-containing compounds such as tri(2-chloroisopropyl) phosphate (TCPP), tris(2-ethylhexyl) phosphate, dimethylpropane phosphonate, triethyl phosphate, and the like. Some of these compounds are described, for example, in S. V. Levchik, E. D. Weil, Polym. Int. 2004, 53, 1901-1929. The flame retardants can preferably be present in an amount of 3 to 6 wt.%, based on the entire composition.

The composition according to the invention can contain at least one catalyst. This enables the curing of the binder (polymer) to be accelerated, thereby preventing or at least significantly slowing down the sinking or collapse of the formed foam. The catalyst also causes the surface of the foamed composition to form a skin more quickly, resulting in the surface remaining sticky for a shorter period of time.

As catalysts, all compounds can be used that are suitable for catalyzing the formation of Si-O-Si bonds between the silane groups of the polymers. Examples include metal compounds, such as titanium compounds, for example titanates like tetra-n-butyltitanate, tetra-n-propyltitanate, tetra-isopropyltitanate, tetraacetylacetonato-titanate, tin compounds, such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, dibutyltin dioctanoate, dibutyltin acetylacetonate, dibutyltin oxide, or corresponding compounds of dioctyltin, tin naphthenate, dimethyltin dinedodecanoate, reaction products from dibutyltin oxide and phthalate esters, organoaluminum compounds, reaction products from bismuth salts or chelating compounds, such as zirconium tetracetylacetonate.

These catalysts can be used regardless of the blowing agent chosen for foam formation.

Provided a catalyst is used, it can be present in an amount up to 5 wt.%, preferably from 0% to 4 wt.%, and more preferably from 0% to 0.5 wt.%, based on the entire composition, in the compositions.

Alternatively, it is also possible to use other catalysts, especially since the previously mentioned catalysts are partly questionable in terms of their toxicity. These include, for example, acidic or basic catalysts. However, these catalysts are not independent of the propellant and must be selected accordingly. Furthermore, it should be taken into account, particularly regarding the amount to be used, that the catalysts can sometimes act as reactants in the reaction forming the propellant and therefore may be consumed.

In the case where carbon dioxide is to be used as a propellant, acidic catalysts such as citric acid, phosphoric acid or phosphoric acid esters, toluenesulfonic acids, and other inorganic acids can be used as catalysts, alternatively or in addition to the above-mentioned metal compounds. The acid also acts as an accelerator for the curing reaction of the binder by accelerating the hydrolysis and condensation of alkoxysilyl groups. Thus, the curing of the composition becomes largely independent of the absolute air humidity, and the composition cures reliably and quickly even under extremely dry conditions. In this regard, toluenesulfonic acids are particularly suitable, which lead to very rapid curing even without the use of another catalyst.

In the case where hydrogen is to be generated as a propellant, basic catalysts can be used as a catalyst, alternatively or in addition to the above-mentioned metal compounds, such as simple bases, e.g., NaOH, KOH, K2CO3, ammonia, Na2CO3, aliphatic alkoxides or K-phenolates, organic amines, such as triethylamine, tributylamine, trioctylamine, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, tetramethylenediamine, quadrol, diethylenetriamine, dimethylaniline, proton sponge, N,N'-bis[2-(dimethylamino)ethyl]-N,N'-dimethylethylenediamine, N,N-dimethylcyclohexylamine, N-dimethylphenylamine, 2-methylpentamethylenediamine, 1,1,3,3-tetramethylguanidine, 1,3-diphenylguanidine, benzamidine, N-ethylmorpholine, 2,4,6-tris(dimethylaminomethyl)phenol (TDMAMP); 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5-diazabicyclo(4.3.0)non-5-ene (DBN); n-pentylamine, n-hexylamine, di-n-propylamine and ethylenediamine; DABCO, DMAP, PMDETA, imidazole and 1-methylimidazole or salts of amines and carboxylic acids and polyetheramines, such as polyether monoamines, polyether diamines or polyether triamines, for example the Jeffamines from Huntsman and Etheramines, such as the Jeffkats from Huntsman, optionally each as (aqueous) solution, can be used. With regard to this, reference is made to the applications WO 2011/157562 A1 and WO 2013/003053 A1.

The type and amount of catalyst are selected depending on the chosen alkoxysilane-functional polymer, the desired reactivity, and the desired blowing agent.

In order to give the formed foam a higher stability, the formed cells must remain stable until the binder cures, in order to prevent the collapse of the polymeric foam structure. The need for stabilization becomes greater the lower the density of the foam is intended to be, that is, the greater the volume expansion is. Stabilization is usually achieved by means of foam stabilizers.

If required, the composition according to the invention may further contain a foam stabilizer. Suitable foam stabilizers include, for example, alkyl polyglycosides. These are obtainable by known methods of the skilled person through the reaction of long-chain monoalcohols with monosaccharides, disaccharides or polysaccharides. The long-chain monoalcohols, which may optionally be branched, preferably have 4 to 22 carbon atoms, preferably 8 to 18 carbon atoms and particularly preferably 10 to 12 carbon atoms in the alkyl group. In detail, the following long-chain monoalcohols may be mentioned: 1-butanol, 1-propanol, 1-hexanol, 1-octanol, 2-ethylhexanol, 1-decanol, 1-undecanol, 1-dodecanol (lauryl alcohol), 1-tetradecanol (myristyl alcohol) and 1-octadecanol (stearyl alcohol). Mixtures of the aforementioned long-chain monoalcohols can also be used. Further foam stabilizers include anionic, cationic, amphoteric and nonionic surfactants known per se, as well as mixtures thereof. Alkyl polyglycosides, EO/PO block copolymers, alkyl or aryl ethoxylates, siloxane ethoxylates, esters of sulfobutyric acid and/or alkali or alkaline earth metal alkanoates are preferably used. EO/PO block copolymers are particularly preferred.

The foam stabilizers can be present in any of the components of the inventive composition, as long as they do not react with each other.

Furthermore, the composition may contain another crosslinking agent (co-crosslinking agent). This enables various properties, such as adhesion to the substrate, improved wetting of additives, and the curing speed of the composition, to be specifically optimized and tailored.

Suitable further crosslinking agents (co-crosslinking agents) are selected from a reactive alkoxysilane or an oligomeric organofunctional alkoxysilane. Preferably, the further crosslinking agent is an oligomeric vinyl-functional alkoxysilane, an oligomeric amino/alkyl-functional alkoxysilane, an oligomeric amine-functional alkoxysilane, an amine-functional alkoxysilane, an alkyl-functional alkoxysilane, an epoxy-functional alkoxysilane, a vinyl-functional alkoxysilane, a vinyl/alkyl-functional alkoxysilane, a mercapto-functional alkoxysilane, a methacryl-functional alkoxysilane, or a silicate ester.

Suitable further coupling agents are, for example: hexadecyltrimethoxysilane, iso-butyltriethoxysilane, iso-butyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, octyltrichlorosilane, octyltriethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, bis(3-triethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)amine, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethyl-3-amino-propylmethyldimethoxysilane, 2-aminoethyl-3-amino-propyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercapto(propyl)trimethoxysilane, 3-methacryloxypropyltrimethoxysilane, methacryloxymethyl-methyldimethoxysilane, methacryloxymethyl-timethoxysilane, 3-methacryloxypropyltriacetoxysilane, ethylpolysilicate, tetraethylorthosilicate, tetramethylorthosilicate, tetra-n-propylorthosilicate, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, vinyltris(2-methoxyethoxy)silane, N-cyclohexylaminomethyltriethoxysilane, cyclohexyl-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-(2-aminomethylamino)propyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, N

If another crosslinking agent (co-crosslinking agent) is used, it can be present individually or as a mixture of several components in an amount up to 10% by weight, preferably up to 7% by weight, and most preferably up to 5% by weight, based on the total composition.

In one embodiment, the composition according to the invention further contains at least one additional component selected from plasticizers, crosslinking agents, water absorbers, organic and/or inorganic fillers and/or other additives.

The plasticizer has the task of making the cured polymer network softer. Furthermore, the plasticizer has the task of introducing an additional liquid component, so that the fillers are completely wetted and the viscosity is adjusted to make the coating processable. The plasticizer can be present in such an amount in the composition that it can sufficiently fulfill the above-mentioned functions.

Suitable plasticizers are selected from derivatives of benzoic acid, phthalic acid, for example phthalates such as dibutyl, dioctyl, dicyclohexyl, diisooctyl, diisodecyl, dibenzyl or butylbenzyl phthalate, trimellitic acid, pyromellitic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, caprylic acid and citric acid, alkyl phosphates, derivatives of polyesters and polyethers, epoxidized oils, C10-C21 alkyl esters of phenol and alkyl esters. Preferred plasticizers are ester derivatives of terephthalic acid, triol ester of caprylic acid, glycol diester, diol ester of aliphatic dicarboxylic acids, ester derivative of citric acid, secondary alkyl sulfonate ester, ester derivatives of glycerin with epoxy groups and ester derivatives of phosphates. More preferred is the plasticizer bis(2-ethylhexyl) terephthalate, trihydroxymethylpropyl caprylate, triethylene glycol bis(2-ethylhexanoate), 1,2-cyclohexanediacetate diisononyl ester, a mixture of 75-85% secondary alkyl sulfonate esters, 15-25% secondary alkane disulfonate diphenyl esters and 2-3% non-sulfonated alkanes, triethyl citrate, epoxidized soybean oil, tri-2-ethylhexyl phosphate or a mixture of n-octyl and n-decyl succinate. Most preferred is a phosphate ester plasticizer, since these can act both as a plasticizer and as a flame retardant.

In the composition, the plasticizer can be present in an amount up to 40 wt.%, more preferably up to 35 wt.%, and even more preferably up to 15 wt.%, based on the entire composition.

In order to prevent an early reaction of the alkoxysilane-functional polymer with residual moisture from components possibly contained in the composition, especially fillers and/or additives, or with humidity in the air, water scavengers are usually added to the composition. This way, moisture incorporated into the formulations is captured. Preferably, the water scavenger is an organofunctional alkoxysilane or an oligomeric organofunctional alkoxysilane, more preferably a vinyl-functional alkoxysilane, an oligomeric vinyl-functional alkoxysilane, a vinyl/alkyl-functional alkoxysilane, an oligomeric amino/alkyl-functional alkoxysilane, an acetoxy/alkyl-functional alkoxysilane, an amine-functional alkoxysilane, an oligomeric amine-functional alkoxysilane, a carbamate silane, an arylalkoxysilane or a methacryloxy-functional alkoxysilane. Most preferred are the water scavengers: di-tert-butoxydiacetoxysilane, bis(3-triethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)amine, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, N-cyclohexylaminomethyltriethoxysilane, vinyldimethoxymethylsilane, vinyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, methacryloxymethyl-methyldimethoxysilane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropyltriacetoxysilane, N-methyl[3-(trimethoxysilyl)propyl]carbamate, N-trimethoxysilylmethyl-O-methylcarbamate, N-dimethoxy(methyl)silyl-methyl-O-methylcarbamate, phenyltrimethoxysilane or combinations thereof.

The amount of water absorber used depends on the moisture content of the components of the formulation, excluding the additional water (component B), and is usually in the range up to 4 wt.%. The water absorbers can be present in an amount of 0.1 to 4 wt.%, preferably from 0.8 to 3 wt.%, and more preferably from 0.8 to 2.5 wt.%, based on the entire composition.

The composition may, in addition to the already described additives, optionally contain conventional auxiliary agents such as dispersing agents, for example based on polyacrylates and/or polyphosphates, pigments, biocides, or various fillers such as vermiculite, inorganic fibers, quartz sand, microglass beads, mica, silicon dioxide, mineral wool, and the like.

Additional additives, such as thickening agents and/or rheology modifiers, as well as fillers, can be added to the composition. As rheology modifiers, such as anti-settling agents, anti-drainage agents, and thixotropic agents, preferably polyhydroxycarboxylic acid amides, urea derivatives, salts of unsaturated carboxylic acid esters, alkylammonium salts of acidic phosphate derivatives, ketoximes, amine salts of p-toluenesulfonic acid, amine salts of sulfonic acid derivatives, as well as aqueous or organic solutions or mixtures of these compounds are used. In addition, rheology modifiers based on pyrogenic or precipitated silicas, or based on silane-treated pyrogenic or precipitated silicas can be used. Preferably, the rheology additive is pyrogenic silica, modified and non-modified layer silicates, precipitated silicas, cellulose ethers, polysaccharides, polyurethane and acrylic thickening agents, urea derivatives, castor oil derivatives, polyamides, and fatty acid amides and polyolefins, provided they are present in solid form, powdered cellulosics and/or suspending agents such as, for example, xanthan gum.

The inventive composition can be packaged as a two-component or multi-component system, wherein the term "multi-component system" also includes two-component systems. The composition is preferably packaged as a two-component system, in which the individual components of the blowing agent mixture are separated from each other in a reaction-inhibited manner prior to use of the composition, and the crosslinking agent is separated in a reaction-inhibited manner from the alkoxysilane-functional polymer prior to use of the composition. The further components of the composition are divided according to their mutual compatibility and their compatibility with the compounds contained in the composition, and they can be contained in one of the two components or in both components. Furthermore, the division of the further components, particularly the solid components, may depend on the amounts in which these components should be present in the composition. Through appropriate division, a higher proportion, relative to the entire composition, can be achieved if necessary. The fire retardant additive can be present in one component or in several components either as a total mixture or as individual components. The division depends on the compatibility of the compounds contained in the composition, so that neither a reaction between the compounds contained in the composition nor mutual interference, nor a reaction of these compounds with the compounds of the other components can occur. This depends on the compounds used.

The subject of the invention is also the use of an inventive composition for sealing openings, cable and pipe penetrations in walls, floors and/or ceilings, joints between ceilings and wall parts, between masonry openings and installed structural components, such as window and door frames, between ceilings and walls, and between external walls and attached facades of buildings for the purpose of fire protection.

The subject of the invention is also a process for foam production, in which the components of a previously described foam system are mixed together at or near the application site, and the mixture is then applied or introduced at the desired location, for example into a slot, a cavity, or onto a surface. This type of foam is referred to as so-called on-site foams.

The subject of the invention is also shaped bodies that are obtainable by the above-described method, wherein foam production can, for example, take place in a mold. It is conceivable to use a shaped body for producing shaped bodies which are used in masonry openings, for example, cable ducts. Preferably, they can also be used for cable, pipe, busbar and/or joint seals. They can also preferably be used as fire protection seals and for producing fireproof adhesives, for coating surfaces and for manufacturing sandwich components or composite panels.

The shape bodies foam up in case of fire and thus prevent the spread of flames, making them suitable as sealing elements, safety devices, fire barriers or coverings. They can thus be used as joints, closures for cable penetrations, or to seal wall openings. The use of a fire protection element as an inner coating of fire-retardant doors, which foams up and provides insulation during a fire, should also be considered. Likewise, the production of door seals or other seals that foam up during a fire and seal the preceding gap is possible. The invention will be explained in more detail below with reference to some examples.

EXEMPLARY IMPLEMENTATIONS

The individual components listed in examples 1 and 2 are mixed and homogenized individually. For application, these mixtures are mechanically mixed together in a container until a homogeneous mixture is achieved and foaming begins.

The fire protection properties of the resulting compositions were determined by macro-thermomechanical analysis using a Macro-TMA 2 device (developed and built by Hilti (HEG) & ASG (Analytik-Service Gesellschaft in Augsburg). For this purpose, each time a round sample with a diameter of d = 45 mm was cut out. The samples were heated to 650 °C at a heating rate of 15 K/min under a load of 100 g. The stability of the resulting ash crust was determined using a Texture Analyzer (CT3 from Brookfield). For this, the sample was penetrated with a T7 probe at a constant speed of 0.5 mm/s. The force used was measured as a function of penetration depth. The higher the force, the harder the ash crust.

Example 1 - Foam system foamed by hydrogen generation (Reference example)

Bestandteil	Menge [Gew.-%]
5,9
3,4
58,6
8,8
9,4
5,7
1,9
1,5
0,9
3,2
0,5
0,1
0,1

Example 2 - Foam system foamed with carbon dioxide (Reference example)

Bestandteil	Menge
22,0
22,0
4,4
2,1
Leitungswasser	11,3
5,9
0,5
12,5
8,6
5,3
1,8
1,4
0,8
0,3
0,5
0,2
0,4

Comparison example

As a reference, the product CP660 from the company Hilti, a polyurethane-based fireproof foam, was used. Tabelle 1: Ergebnisse der Bestimmung der Aschekrustenstabilität

Vergleichsbeispiel	4791
Beispiel 1	6039
Beispiel 2	3266

As can be seen from Table 1, the reference examples provide a firm ash crust, whereas the composition foamed with carbon dioxide results in a harder ash crust than that of the commercially available product CP 660.

Example 3 - Foam system inflated with carbon dioxide; Fire test

In order to evaluate whether the inventive compositions are suitable as fireproof sealing materials, a composition consisting of the components listed below was filled into a commercially available 2K cartridge with a mixing ratio of 3:1 and applied using a static mixer. At that time, the respective components of the propellant components were kept separate from each other, and the co-crosslinkers were kept separate from the polymers.

A fire test for cable penetrations was conducted according to EN 1366-3 (Annex B). For this purpose, a cellular concrete wall with four openings of 20x20 cm and 15 cm depth was used, equipped with the following penetrations: C- and E-cables and a conduit (d = 32 cm). The tested foam as well as a commercially available product were placed into the openings and tested for 90 minutes in a fire test. On the non-fire side, the temperature on the surface of the foam, the individual cables and the conduit was measured. The time at which the temperature exceeds the ambient temperature by 180 °C (T-rating) was recorded for each penetration element. OK means that T < 180 °C throughout the entire test.

22,6
22,6
4,3
0,2
0,2
1,1
3,0
0,6
9,9
6,1
2,1
1,5
0,9

13,8
Leitungswasser	9,2
0,5
0,3
0,3
0,3
0,5

Tabelle 2: Ergebnisse aus dem Brandtest

1. Leerrohr
2. C-Kabel	68 min	63 min
3. E-Kabel	73 min	74 min
4. Schaumoberfläche

From Table 2, it can be seen that the foam from the inventive composition provides better fire protection than the foam from the commercially available product.

Based on the examples, it was shown that the inventive compositions are excellent as fire protection foams.

Claims (16)

1. Foamable multi-component composition forming an insulating layer with at least one alkoxysilane functional polymer, which terminates and/or has alkoxy functional silane groups of general formula (I) as side groups along the polymer chain         -Si(R¹)_m(OR²)₃-_m     (I),

   in which R¹ stands for a linear or branched C₁-C₁₆ alkyl residue, R² for a linear or branched C₁-C₆ alkyl residue and m for an integer from 0 to 2, with a propellant mixture and with a crosslinking agent,

   in which the individual components of the propellant mixture are separated from each other in a way that inhibits reaction before the composition is used and the crosslinking agent is separated from the alkoxysilane functional polymer in a way that inhibits reaction before the composition is used, characterised in that the multi-component composition contains at least one fire protection additive forming an insulating layer in an amount of 12 to 60% by weight with reference to the whole multi-component composition.
2. Composition according to claim 1, in which the propellant mixture comprises compounds, which react with each other after they are mixed, forming carbon dioxide (CO₂), hydrogen (H₂) or oxygen (O₂).
3. Composition according to claim 2, in which the propellant mixture comprises an acid and a compound, which may react with acids, forming carbon dioxide.
4. Composition according to claim 2, in which the propellant mixture comprises a base and a compound, which has Si-bonded hydrogen atoms.
5. Composition according to one of the previous claims, in which the polymer comprises a scaffold, which is selected from the group consisting of a polyether, polyester, polyether ester, polyamide, polyurethane, polyester urethane, polyether urethane, polyether ester urethane, polyamide urethane, polyurea, polyamine, polycarbonate, polyvinyl ester, polyacrylate, polyolefin, polyisobutylene, polysulphide, rubber, neoprene, phenolic resin, epoxy resin and melamine.
6. Composition according to one of the previous claims, in which the alkoxysilane functional polymer carries at least two alkoxy functional silane groups.
7. Composition according to one of the previous claims, in which the crosslinking agent is water or a component containing water.
8. Composition according to one of the previous claims, in which the fire protection additive forming an insulating layer contains at least one thermally expandable compound and/or a mixture, which contains at least one dehydration catalyst, at least one gas former and, if necessary, at least one carbon supplier.
9. Composition according to claim 8, in which the fire protection additive also contains an ash crust stabiliser.
10. Composition according to one of the previous claims, in which the composition also contains a further crosslinking agent (co-crosslinking agent).
11. Composition according to one of the previous claims, in which the composition also contains a catalyst, which catalyses the formation of Si-O-Si bonds between the alkoxy functional silane groups of the alkoxysilane functional polymers.
12. Composition according to claim 11, in which the catalyst is selected from metal compounds, acidic or basic compounds.
13. Composition according to claim 11 or 12, in which the catalyst is selected from amine compounds.
14. Composition according to one of the previous claims, in which the composition also contains at least a further component, which is selected from the group consisting of softeners, water getters, inorganic fillers and/or further additives.
15. Use of a composition according to one of claims 1 to 14 for foam-filling openings, cable and pipe feed-throughs in walls, floors and/or ceilings, gaps between ceilings and wall parts, between wall openings and structural parts to be installed, such as window and door frames, between ceilings and walls and between outside walls and façades suspended from buildings for the purpose of fire protection.
16. Moulding obtainable from a composition according to one of claims 1 to 14, in which the relevant components are mixed with each other and a mould is foam-filled with the mixture.